complete Desgin-1

Problem3.java

@@ -0,0 +1,40 @@
+// Time Complexity: O(1)
+// Space Complexity: O(N)
+
+class MinStack {
+    private ArrayList<int[]> st;
+
+    public MinStack() {
+        st = new ArrayList<>();
+    }
+
+    public void push(int val) {
+        int[] top = st.isEmpty() ? new int[]{val, val} : st.get(st.size() - 1);
+        int min_value = top[1];
+        if (min_value > val) {
+            min_value = val;
+        }
+        st.add(new int[]{val, min_value});
+    }
+
+    public void pop() {
+        st.remove(st.size()-1);
+    }
+
+    public int top() {
+        return st.isEmpty() ? -1 : st.get(st.size() - 1)[0];
+    }
+
+    public int getMin() {
+        return st.isEmpty() ? -1 : st.get(st.size() - 1)[1];
+    }
+}
+
+/**
+ * Your MinStack object will be instantiated and called as such:
+ * MinStack obj = new MinStack();
+ * obj.push(val);
+ * obj.pop();
+ * int param_3 = obj.top();
+ * int param_4 = obj.getMin();
+ */

Sample.java

@@ -1,7 +1,34 @@
-// Time Complexity :
-// Space Complexity :
-// Did this code successfully run on Leetcode :
-// Any problem you faced while coding this :
+// Time Complexity : O(1)
+// Space Complexity : O(1) -> O(1000001)
+// Did this code successfully run on Leetcode : Yes
+// Any problem you faced while coding this : Initialized the boolean set with only 100 as the limit
 
 
 // Your code here along with comments explaining your approach
+class MyHashSet {
+    boolean[] set;
+
+    public MyHashSet() {
+        set = new boolean[1000001];
+    }
+
+    public void add(int key) {
+        set[key] = true;
+    }
+
+    public void remove(int key) {
+        set[key] = false;
+    }
+
+    public boolean contains(int key) {
+        return set[key];
+    }
+}
+
+/**
+ * Your MyHashSet object will be instantiated and called as such:
+ * MyHashSet obj = new MyHashSet();
+ * obj.add(key);
+ * obj.remove(key);
+ * boolean param_3 = obj.contains(key);
+ */